regions: add more helpers

Fill out functions to get the offset and size for both
regions and region_devices. Additionally add a helper for
memory mapping an entire region_device.

Change-Id: I8896eaf5b29e4a67470f4adc6f5b541566cb93b5
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/10215
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

src/lib/region.c

@@ -20,11 +20,6 @@
 #include <region.h>
 #include <string.h>
 
-static inline size_t region_offset(const struct region *r)
-{
-	return r->offset;
-}
-
 static inline size_t region_end(const struct region *r)
 {
 	return region_sz(r) + region_offset(r);